Method of treating leather



S. O. HAHN.

METHOD OF TREATING LEATHER.

APPLICATION FILED FEB. 16, I920.

Lsaggw, Patented Feb. 22, 2921.

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' umrao STATES,

I SAMUEL OTIS HAHN, OF LINCOLN, NEBRASKA, ASSIGNOR TO THE CHROME LEATHER PATENT oFFicE,

AND RUBBER TIRE COMPANY, 1110., OF PUEBLO, COLORADO.

mn'rnon or r nnn'rme LEATHER.

Application filed February 16, 1920. Serial No. 859,186

To all whom it may concern:

Be it known that I, SAMUEL O'rrs HAHN, a citizen of the 'United States, residing at Lincoln, in the county of Lancaster and State ofNebraSka, have invented certain new and usefulImprovements in Methods of Treating Leather and I do declare the following 7 to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and figures of reference marked thereon, which form a part of this specification.

This invention relates to a method of preparin leather'to receive a vulcanized coating rubber to provide articles for industrial purposes, such as belts, sheets, soles,

- rubber tires, insoles and the like, the .pri-

natural characteristics of the leather will not.

be impaired during the process. 1

As an example of my invention I prefer to use chrome leather or cowhide of appropriate thickness and impregnate v the body of leather to a suitable degree beyond-the surface or surfaces with rubber cement, having a relatively low sulfur content,

- I have also taken ordinary commercial rubber cement and permitted the same to stand a sufficient time to allow natural precipitation of the sulfur and then used the material above the precipitation containing [is provided, consisting of the exible rubber whatever sulfur remained therein, and I have found that this admirably serves the purpose intended.

The chrome eather may be treated on one or both sides by rubbing the low sulfur content cement thoroughly into the surface or surfaces thereof and then allowing the leather thus treated to stand for a period of approximately one-half hour at normal tem perature to permit the cement to set; z'. e., permit the volatile filler to evaporate and leave the adhesive content'of the cement as a surface.

In order to get the best results, the treatment just described shouldbe repeated about three times, allowing thirty minutes after each application of the cement, whereupon the leather is in condition to receive the vulcanizing coating or layer.

Specification of Letters Patent. Patented Feb. 22, 1921. I

After the leather istreated as above de-,

scribed, the vulcanizing' sheet or layer of rubber may be applied to the surface thereof and the sheet 0 treated leather and sheet or' sheets of rubber to' be vulcanized thereto may be subjected to a vulcanizing treatment.

consisting of application of dry heat. The time required to cure or vulcanize the rubber on the leather so treated will depend upon the qualit 'or character of the rubber used but usual yabout two hours treatmentat 280 F.'., under pressure, will be sufficient to;

Chrome leather or cowhide has consider- 7 accomplish the desired result.

able tensile strength but so far as I am aware, it has been considered to be impractical before my invention to vulcanize rubber thereto, due to'the inability to cause the rubber to combine at the surface with the leather so that the requisite bond might be effected. By treating the leather in the-manner described, the natural characteristics of and the vulcanized sheet. I

If the leather is impregnated with low sulfur content cement on both sides and then the surfaces are covered with sheets of rubber or rubberized fabric, as described, an efiicient, durable and exceeding-l flexible product will be provided, consistm of a core or inner layer of the leather wit outer sheathing-s of rubber, the whole being in effect an integral mass.

Under some conditions it is advisable to vulcanize only one side of the leather as,

- for example, where the leather is the insole eluding water and moisture but permitting an inner sole of leather to be' in effect an integral part of the outer' sole so that the wearers foot will come in contact with the -leather only and not be subjected to the inconveniences incident to contact of rubber with the fcsti The uses to which the finished products may be placed are too ni'uititudinous to enumerate but will be apparent that the products wiil be for use in connecing machine or drier into which the finished tion Withbelts tires flexible sheetings of various kinds, utensils, boots and shoes, etc.

" In'the drawings,

Figure I is a perspective view of a sheet of leather previous to being treated. g Fig. II is a similar View, showing the leather ir'n regnated with the cement, and Fig. II is a sectional view through a cursheet may be placed for curing.

The sheet. 1 is shown as consisting of a piece-of leather of appropriate'thickness, adapted to have its surfaces, either 2 or 3 or both,-impregnated with the cement, preferably of low sulfur content, above speclfied,

' in the manner described heretofore, and

' similar action, the sheet of leather so treated after etch application of. the cement, which should be thoroughly applied by rubbing or is exposed to the air to permit the cement to set. By virtue of thesaid rubbing or similar action in the application of the cement to the leather, the pressure. incident to the rubbing forces the cement into a portion of the body of the leather beyond the surface of theleather. Whenthe sheet so treated is in proper condition, it is subjected to a dry heat in the curing device 4, con

ventionally shown as having a receivin chamber 5'and parallel heat conduits 6 an 7. The treating device consists of twoparts- 8 and 9, fastened together by fastening devices 10. The particular form of dev ce is unimportant as any device for holding the product under pressure while dry heat is applied thereto may be used. The manner 7 of application of dry heat to the roduct is also unim ortant except that the eat must be applie uniformly to all surfaces or parts other by the cement so that, the structure ma be built up for any number of layers desire provided there is a suficient body of rubber between layers to form the adhesion.

he iilre may be treated in the t steam must not be used in eather sheet. in practice have found that this treatment does impair the quaiity or characteristics of the ieatherfin any manner. The leather remains flexible and pliable and adequately adheres to the coating vulcanized upon it.

What I claim and desire to secure by Letters-Patent is: y

L The method of treating leather which consists in separating from ordinary .com- 'mercial rubber cement aportion of the sulfur thereof to produce a cement of a decidedly lower sulfur content than the orthe surface of the latter to impregnate the leather and subsequ tly vulcanizing rubber to the ieather so treated whereby the rubber and leather are united into substantially an integral mass. A i

2. The method of treating leather which consists in forcin rubber cement ofa-decidedly lower suli ur content than ordinary commercial rubber cement into the body of chrome leather a suitable degree beyond the surface of the. latter to thoroughly impregnate the body of the leather with the gum constituent of the cement and subsequently vulcanizing rubber to the leather so treated whereby the rubber leather and cement are united into substantiall an integral mass.

. In testimony whereo I afiix my signature.

' SAMUEL o'rIs HAHN. 

